The only way for it to be risk free is to send a young baby boy and a young baby girl to live in Mars under 'living' conditions, and for them to start their own generation. I wouldn't think, the whole human population could be exported to Mars, due to financial issue and other issues involved. This may seem to be fantasy, but in 20 years of progress, who knows?

I reckon, and sort of agree with abubin on his statement for the human evolution. We do not certainly, end up as modern human beings as of we are, out of the blue, it took time for the evolution to take place as explained in Darwin's theory of Evolution, and end up as who we are today.